The technique of wireless charging is a technique which utilizes the electromagnetic wave induction principle and the related technique of alternating current induction, and corresponding coils are used on a transmitting end and a receiving end to transmit and receive alternating signals that produce induction to charge. At present, electromagnetic-induction-type wireless charging is commonly used. The principle of the electromagnetic-induction-type wireless charging is that a primary coil is set on one side of a charger, a alternating current with a certain frequency is loaded on the primary coil, a certain current is produced on the secondary coil by the electromagnetic induction, thereby the energy is transferred from the transmitting end to the receiving end. The less the differences between the sizes of the secondary coils are, the less the energy transfer loss is, and the higher the efficiency of the wireless charging is. However, the primary coil on the wireless charger is made relatively big, aiming that the secondary coil is placed on what position of the mobile terminal to make the differences between the sizes of the secondary coils become less, we need to find the position on the smart mobile terminal to place the secondary coil.
On the other hand, frequency modulation (FM) radios are more and more applied in wireless terminals especially in mobile phones. Since the FM broadcasting band is generally between 80 MHz and 110 MHz, thereby an antenna of the FM radio is required between 70 cm and 100 cm. It is not realistic to make such a long antenna on Printed Circuit Board (PCB) of the wireless terminal. The traditional method is to use an earphone wire as the antenna of the FM radio, but in this case, if earphones are not inserted, a FM radio function is unable to be used, thereby the inconvenience is caused.